Tunnel Lighting Design And Requirements Dizaynî û Tirêbazên Bistîna Tonnelayê
Tunnel lighting bûyî ye ku çareserî çareseriya pêşkeftinîna dawilî yên navçeyê di navçey de. Di heman demê de, pirsa dawilî ya navçeya jor û derveya navçeyê li ser şopandin û derdina navçeya wekheviyê heye. Ew dizayn di viriya yek ji xelên nîvendî yên navçeyê de ye.
Bi çava Tunnel Lighting bûyî ye?
Di dema xweşan de navçeya wekheviyê bi rêgeke ku werbigire be li ser ronaya waneyê were bigirin.
Tenaha wekhevî û tenaha êzdana mezin û ku tunnel lighting parêwend bide.
Difference between Tunnel Lighting and Road Lighting
Heke bi rêgeke lighting navçeya wekheviyê bi road lighting berbend bike, dîtin da ku taybetmendiyên lighting navçeya wekheviyê divê li ser xelên nîvendî yên navçeyê di dema rojan de hatine înde.
Lê di heman demê de, li ser ronaya waneyê, factorekên bikarhatîn ji bo şema lighting tikarek di dema xweşan de ne.Sera problemê di dema rojan de ye bi rêgeke navenda navçeyê. Heke çavka mira li ser dawilî ya dema rojan ve were adapte kirin, tune nebe ku bi dawilîya zêdetir bibînin di sereya navçeyê de herdem. Lêm li ser ronaya waneyê, nebe ku vê problemê bi dawilîya zêdetir bibînin ji gelek dema rojê.
Adaptability Criteria of Tunnel Lighting Design
Li dema dest pêkirin, lighting di pêşî navçeyê de divê li ser adaption state ya çavka re were.
Dawilîya li ser çavka dark adapted di dema xweşan de di navçeyê de piştgiri bike.
Luminaires divê bêrber bike bi rêgeke ke transition from the highest to lowest luminance levels li ser tarîqa yek bi yek were bikin bi rêgeke ke çavka wextiyan bike li ser adaption.
What is 40 m Length Rule for Tunnel Lighting?
Xel navçeyê genelî 40m e. Ev xel li ser tarîka yek bi yek were çêkerin.
Li ser figura, di rule 40m de dîtin da ku:
Rojek din di navçeyê de li ser derê 15 m were bicîh bikin.
Derê di objekt û derveya navçeyê de nebe ku 15 m bibe.
Surface-i ronaya navçeyê divê li ser rojek din bicîh bikin bi rêgeke ke objekt di ronaya navçeyê de were dikarin.
Biyay navçeyê divê 200 cm bibe, objekt di sereya navçeyê de li ser point 100 m li ser ronaya navçeyê û 1.5 meter li ser ronaya navçeyê were dikarin.
Rest 25 m di 40 m de li ser lighting design were bikin ji bo gradual luminance adaptability level of human eyes. 25 m xel minîmal li ser navçeyê e. Divê zêdetir bibe.
Rule 40 m li ser tunnel lighting tenha li ser tunnels straight level bêdarîn ku heavy traffic loading netine.
Special tunnel lighting divê were bikin heke:
Curve di navçeyê de nebe an di navçey approach road de,
Dips an exit view frequently lost due to the presence of interviewing vehicles.
Classification of Inside Road Length of Tunnel
Length-i ronaya navçeyê divê li ser 4 zones were divide bikin. Wan in:
Threshold zone
Transition zone
Interior zone
Exit zone
Threshold Zone
Threshold zone pêşî navçeyê ye. Walls û surface-i ronaya di threshold zone de divê li ser her objekt were bicîh bikin.
Hêza li ser ev zone bike:
Heke driver di dema rojan de li ser entrance-i navçeyê were yek, çavka mira li ser high level day time luminance were adapte kirin.
Navçeyê li ser outside luminance level zêdetir bibe. Objekt û details-i interior-i navçeyê nebe dikarin.
Threshold zone di long tunnel de special lighting di dema rojan de hewce ye. Li ser visual reliability li ser acceptable level driver bike.
What is the Luminance Level at Threshold Zone?
Investigation di tunnel lighting de were bikin. Dîtin da ku objekt 20 cm × 20 cm enough li ser distance 100 m li ser threshold zone were dikarin. Outside adaptation luminance influence on luminance needed in the threshold zone in order to see any object inside the tunnel.
Figure given below is taken from the technical investigation of CIE.
Luminance in the threshold zone gives the variation in the luminance contrast. It is over a range of values 7 Lux/cd/sq-m.
The figure above shows that outside adaptation luminance level is greater than about 100 cd/sq-m.
The luminance level (Lth) in the threshold zone should be equal to or greater than 0.1 times the adaptation luminance (La).
What Happens for a Moving Observer with Non Uniform Luminance in Threshold Zone?
In practice, of course, the luminance of the surroundings of a tunnel entrance is not uniform.
When an observer approaches towards a tunnel, the relative dark tunnel entrance and its surrounding lightened occupancy will be caught in driver’s total field of view. When he just enters the tunnel with already adapted outer side day light brightness, his eyes cannot adapt the brightness of inside tunnel. But adaptation of the driver’s eyes is continuously changing. But after a short while of his approaching, luminance distribution inside the tunnel will be adapted but with time lag.
What is the Threshold Zone Length?
The threshold zone length must be equal to the stopping distance from the start of tunnel entrance including extra distance sufficient for an object with proper back ground luminance.
Stopping distance is the safest distance from the point of taking decision to stop inside the tunnel.
In this length, obstacle must be clearly visible to a driver approaching the tunnel entrance.
Transition Zone
After the threshold zone, transition zone is calculated. The adaptation luminance at the transition zone is achieved easily by the viewers.
Before transition zone, somewhere between the stop decision point and the tunnel entrance, the luminance within a driver’s field of vision starts to decrease rapidly. This causes a change in the adaptation state of the eyes. So in the transition zone, adaptation forhuman eyes is very easy.
The luminance gradient in the transition zone can be tolerated.
There is yet no accurate information on how the value luminance should be sustained in practice for drivers who are much closer to the tunnel entrance than the stop decision point.
Above figure shows the permissible course of the luminance in a tunnel for a driving speed of 80 km/h relative to the equivalent adaptation luminance at the stop decision point.
Where,
Lst is the equivalent adaptation luminance at the stop
